1. Field of the Invention
The present invention relates to distributed electronic systems.
2. Description of the Related Art
In a distributed electronic system, a number of electronic modules are decentralized, rather than a single integrated module being employed. An example of such a distributed electronic system is provided in my co-pending U.S. Pat. No. 5,760,587, filed Jun. 28, 1995. This system is a system for measuring the voltages of the series-connected "traction batteries" of an electric vehicle. These batteries provide the electric power for propulsion of the vehicle.
The distributed system in that disclosure has a plurality of battery measurement modules equal in number to the number of traction batteries. One of the battery measurement modules is connected across each of the batteries. The battery measurement modules are coupled to each other and to a central controller via a data bus. The central controller collects and analyzes battery voltage data from the various battery measurement modules. Such a distributed battery measurement system has considerable advantages over a centralized battery measurement system, in which one battery measurement module is coupled to all of the batteries.
In employing such a distributed electronic system, it is important for the central controller to be able to distinguish among the various battery measurement modules. This ability is needed so the central controller knows which battery measurement modules have sent the various data received by the central controller on the data bus. The central controller may also wish to transmit a command to a specific battery measurement module via the data bus.
One way that the battery measurement modules can be distinguished is by assigning each battery measurement module to be installed in a vehicle an address prior to installation of the module into the vehicle. This can be done (for example) in the battery measurement module's manufacturing facility, where for a vehicle having 28 batteries, battery measurement modules could be assigned addresses from one to 28. A battery measurement module's assigned address would be carried in that module's non-volatile memory for the life of the module. Although this method can work, it has substantial complications. Specifically, after the assignment of different addresses, the modules are no longer identical. Thus, the facility which manufactures the modules must keep track of the assigned addresses of each module, as must the facility which assembles the vehicles containing the modules. Battery measurement modules with duplicate addresses cannot be accommodated on the same vehicle. As an electric vehicle can have dozens of batteries, keeping track of dozens of unique battery measurement modules can be a substantial task. This task can add cost, complexity and errors in the production of an electric vehicle.
Therefore, a more efficient method for assigning addresses to electronic modules in a distributed electronic system will provide advantages over the prior art.